MicroRNA-21 regulates biological behaviors in papillary thyroid carcinoma by targeting programmed cell death 4.

BACKGROUND:Our recent study has found that microRNA-21 (miRNA-21) was significantly upregulated in papillary thyroid carcinoma (PTC) tissues compared with nontumor tissues by using miRNA microarray chip. However, the function of miRNA-21 is unknown in PTC. The aim of this study was to investigate the roles of miRNA-21 in PTC and the mechanism of gene regulation by it. METHODS:We transfected PTC cell line (TPC-1) with pEZX-eGFP-miRNA-21 plasmid to determine the biological functions of miRNA-21. Western blot assay was applied to investigate the correlation between miRNA-21 and programmed cell death 4 (PDCD4) expression in TPC-1 cell line. RESULTS:Overexpression of miRNA-21 could significantly enhance proliferation and invasion and inhibit the apoptosis of TPC-1 cells. In addition, miRNA-21 and PDCD4 expression showed a significantly negative correlation in TPC-1 cells. CONCLUSIONS:These data suggest that miRNA-21 may play an oncogenic role by directly targeting PDCD4 in the cellular processes of PTC. In addition, the findings in our present study also may represent new clues for the diagnostic and therapeutic strategies in the treatment of PTC.